Menu

EWG's Tap Water Database — 2021 UPDATE

Donate

Chloroform

Texas State University - San Marcos

Chloroform, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Chloroform and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Read More.

In addition to tap water disinfection, chloroform pollution in the environment also comes from industrial discharges from pulp and paper mills, and from urban wastewater effluent. Human studies show that chloroform damages the kidneys, liver and central nervous system. In animals, chloroform causes infertility, birth defects and cancer.

Click here to read more about disinfection byproducts.

MORE ABOUT THIS CONTAMINANT

 

101

Samples

0

Samples exceeding legal limit (MCL)

27

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
20140.894 ppb168ND - 2.90 ppb
20150.441 ppb176ND - 1.80 ppb
20160.335 ppb173ND - 3.20 ppb
20170.194 ppb173ND - 1.20 ppb
20180.341 ppb175ND - 1.40 ppb
20190.141 ppb172ND - 1.40 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.4 ppb

The EWG Health Guideline of 0.4 ppb for chloroform was proposed in 2018 by the California Office of Environmental Health Hazard Assessment as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

ppb = parts per billion

All test results

Date Lab ID Result
2014-03-10AC46191ND
2014-03-10AC461922.10 ppb
2014-03-10AC46193ND
2014-03-10AC461951.70 ppb
2014-06-02AC555822.90 ppb
2014-06-02AC556141.000 ppb
2014-06-02AC555811.30 ppb
2014-06-02AC556082.30 ppb
2014-08-26AC65242ND
2014-08-26AC65248ND
2014-08-26AC65246ND
2014-08-26AC652431.30 ppb
2014-11-10AC71516ND
2014-11-10AC71510ND
2014-11-10AC71511ND
2014-11-10AC715141.70 ppb
2015-01-23AC77452ND
2015-01-23AC77455ND
2015-01-23AC77453ND
2015-01-23AC774491.000 ppb
2015-06-08AC94978ND
2015-06-08AC948941.10 ppb
2015-06-08AC94898ND
2015-06-08AC948961.10 ppb
2015-06-08AC94892ND
2015-09-10AD06515ND
2015-09-10AD06530ND
2015-09-10AD06522ND
2015-09-10AD06520ND
2015-12-01AD148981.30 ppb
2015-12-01AD14870ND
2015-12-01AD148731.20 ppb
2015-12-01AD149031.80 ppb
2016-02-25AD25745ND
2016-02-25AD25705ND
2016-02-25AD25674ND
2016-02-25AD25676ND
2016-02-25AD256731.40 ppb
2016-06-16AD40950ND
2016-06-16AD40946ND
2016-06-16AD40944ND
2016-06-16AD409471.10 ppb
2016-08-03AD46866ND
2016-08-03AD46864ND
2016-08-03AD46865ND
2016-08-03AD46868ND
2016-10-17AD53392ND
2016-10-17AD53390ND
2016-10-17AD53391ND
2016-10-17AD533933.20 ppb
2017-02-21AD71252ND
2017-02-21AD71264ND
2017-02-21AD71250ND
2017-02-21AD712461.000 ppb
2017-04-20AD80428ND
2017-04-20AD803781.10 ppb
2017-04-20AD80380ND
2017-04-20AD80376ND
2017-04-20AD80375ND
2017-07-06AD884671.20 ppb
2017-07-06AD88470ND
2017-07-06AD88469ND
2017-07-06AD88472ND
2017-10-18AE01313ND
2017-10-18AE01334ND
2017-10-18AE01321ND
2017-10-18AE01316ND
2018-02-05AE12243ND
2018-02-05AE12161ND
2018-02-05AE12154ND
2018-02-05AE12151ND
2018-02-05AE12158ND
2018-04-09AE21623ND
2018-04-09AE21634ND
2018-04-09AE215961.000 ppb
2018-04-09AE21605ND
2018-07-09AE325971.10 ppb
2018-07-09AE325981.000 ppb
2018-07-09AE325841.40 ppb
2018-07-09AE325821.30 ppb
2018-10-02AE42339ND
2018-10-02AE42333ND
2018-10-02AE42332ND
2018-10-02AE42336ND
2019-01-15AE49833ND
2019-01-15AE49783ND
2019-01-15AE49789ND
2019-01-15AE49788ND
2019-01-15AE49787ND
2019-04-29AE63911ND
2019-04-29AE63895ND
2019-04-29AE63893ND
2019-04-29AE639081.000 ppb
2019-07-09AE73650ND
2019-07-09AE73649ND
2019-07-09AE736511.40 ppb
2019-07-09AE73645ND
2019-10-03AE85627ND
2019-10-03AE85623ND
2019-10-03AE85628ND
2019-10-03AE85622ND